Ask early, in the right form
Distance students ask too late and too vaguely.
Part-time distance students consistently report having struggled alone with something a tutor could have resolved in two minutes. The delay is partly reluctance and partly that the question only becomes askable once the person understands it well enough to phrase it.
The form that gets a fast useful answer is specific: here is what I am trying to do, here is what I tried, here is where it stopped making sense. That takes five minutes to write and it frequently resolves the problem in the writing.
Timing matters practically. A question sent the night before a deadline may not be answered in time, and the same question sent ten days earlier almost certainly will. That is another argument for starting early rather than a criticism of anybody's responsiveness.
Where a course provides no reliable channel for questions, which some do, that is a genuine deficiency worth raising with the provider rather than absorbing, since it disproportionately affects the students studying alone.
The other reason to read the assessment early is that it frequently reveals a choice. Many assessments allow the student to select a topic, a case or an organisation, and choosing one connected to your own work makes the research faster and the writing better, but only if the choice is made before the reading rather than after.